RU174178U1 - Pulsed neutron generator - Google Patents

Abstract

The utility model relates to the field of physical instrumentation, in particular to neutron radiation sources and is intended for use in the development of neutron and x-ray generators. The technical result of the utility model is to increase stability, generator service life with minimum dimensions. The technical result is achieved in that the pulsed neutron generator comprises a neutron tube, a storage capacitor, a choke and a high-voltage transformer with a multi-row secondary winding with multilayer paper-film insulation, made on a closed magnetic circuit having two cores and two located in a sealed enclosure filled with a liquid dielectric; yoke from electrical steel, the output of the secondary winding is connected to a bowl-shaped screen and a vacuum neutron tube located in it, longitudinal The transformer windings are arranged perpendicular to the longitudinal axes of the neutron tube and the casing. The secondary winding of the high-voltage transformer is made on one core of a closed magnetic circuit, on the other core there is another high-voltage winding wound with a wire with high resistivity, connected to a bowl-shaped screen and the beginning of the secondary winding. 2 ill.

Description

The utility model relates to the field of physical instrumentation, in particular to neutron radiation sources, and is intended for use in the development of neutron and x-ray generators.

A small-sized neutron generator is known that contains a neutron tube and a high-voltage power supply source, made on a storage capacitor connected between a high-voltage power source and the primary winding of a high-voltage pulse transformer (in the case of a bipolar power supply of a neutron tube, between the primary windings of high-voltage pulse transformers). Geophysical equipment. Subsoil, issue. 43, 1970 .-- S. 132-146. However, this neutron generator has large dimensions and a small resource of work.

Known pulsed neutron generator containing coaxially placed in a common housing a neutron tube, a storage capacitor and a high voltage transformer with a multi-row secondary winding, made on the frame in the form of a hollow cylinder made of ferrite with a metal bottom, with inter-row insulation, protruding outside the rows and laid in layers on a metal the bottom of the frame, electrically connected to the end of the secondary winding of the transformer and to the target part of the neutron tube. USSR copyright certificate No. 1158023, IPC Н05Н 5/00, 04/30/1994.

With the coaxial arrangement of the neutron tube and the high-voltage transformer, the magnetic field inside the dielectric frame negatively affects the operation of the neutron tube, namely, it leads to an increase in the number of discharges inside the neutron tube and a decrease in the integral neutron yield.

With this mutual arrangement of the transformer windings and the generator housing, the efficiency of the high-voltage transformer is not high, since the transformer windings are wound on an open ferromagnetic core.

In addition, this mutual arrangement of the transformer windings and the case negatively affects the efficiency of high-voltage transformers, since the case forms a "short-circuited coil" with respect to the windings of the high-voltage transformer. To reduce the influence of the housing on the parameters of the high-voltage transformer, screens of ferromagnetic material of a sufficiently large thickness are installed between them.

Also known is a pulsed neutron generator containing placed in a sealed enclosure filled with a liquid dielectric, a neutron tube, a storage capacitor, a choke and a high voltage transformer. The high-voltage transformer is made on a closed core of electrical steel, the longitudinal axes of the transformer windings are perpendicular to the longitudinal axes of the neutron tube and the casing. Patent for invention RU 2603016, IPC Н05Н 3/06, 11/20/2016. This technical solution was made as a prototype.

In the well-known generator, the effect of the "closed loop" is eliminated due to the perpendicular arrangement of the longitudinal axes of the windings of the high voltage transformer and the housing, and the efficiency of the transformer is increased due to the closed magnetic circuit made of electrical steel.

However, during prolonged operation of the generator and depletion of the resource, sometimes the neutron tube source fails. The resistance of the neutron tube in this mode is hundreds of megohms, while the “idle” mode of the high-voltage transformer appears, and the voltage on its secondary winding reaches a value of 200 to 220 kV.

To eliminate electrical breakdown, it is necessary either to create powerful insulation, which increases the overall mass characteristics of the generator, or to reduce the amplitude of the accelerating voltage, which leads to a decrease in the neutron yield.

The technical result of the utility model is to increase stability, generator service life with minimum dimensions.

The technical result is achieved in that in a pulsed neutron generator containing placed in a sealed enclosure filled with a liquid dielectric, a neutron tube, a storage capacitor, a choke and a high voltage transformer with a multi-row secondary winding with multilayer paper-film insulation, made on a closed magnetic circuit having two cores and two yokes of electrical steel, the output of the secondary winding is connected to a bowl-shaped screen and a vacuum neutron tube located in it, The axes of the transformer windings are perpendicular to the longitudinal axes of the neutron tube and the case, the primary and secondary windings of the high-voltage transformer are made on one core of a closed magnetic circuit, and another high-voltage winding is wound on the other core, wound with a high resistivity wire connected to a cup-shaped screen and the beginning of the secondary winding and housing.

The essence of the utility model is illustrated by drawings, where: 1 - a metal case, 2 - a neutron tube, 3 - a high-voltage transformer, 4 - a yoke of a closed magnetic circuit, 5 - cores of a closed magnetic circuit, 6 - a primary winding, 7 - a secondary multi-row winding, 8 - additional high-voltage a winding from a wire with high resistivity, performing the functions of load resistance, 9 - paper-film insulation, 10 - capacitor of a neutron tube power source, 11 - inductor, 12 - storage capacitor, 13 - cup-shaped m the metallic screen 14 - Generator cover, 15 - the temperature compensator 16 - the bushing is sealed.

In FIG. 1 shows a longitudinal section through a pulsed neutron generator.

In FIG. 2 shows a cross section AA, where H1 is the beginning, and K1 is the end of the primary winding of the high voltage transformer, H2 is the beginning, and K2 is the end of the secondary winding of the high voltage transformer; N load - the beginning, and K heat. - the end of the additional winding of the high voltage transformer, performing the function of load resistance.

The resistance value of the additional winding is selected based on the value from 25 to 30 kOhm, i.e. the resistance is slightly greater than the resistance of a neutron tube when an ion source is triggered. The value of the resistance of the tube during operation is from 10 to 15 kOhm.

The generator is made according to the scheme of the neutron tube with a grounded source.

The generator is placed in a sealed metal case 1, filled with a liquid dielectric, inside which a neutron tube 2 is installed, a pulsed high-voltage transformer 3 on a closed magnetic circuit. The closed magnetic circuit has two yokes 4 and two cores 5 made of plates of electrical steel.

The primary winding 6 is located symmetrically relative to its ends on one core 5, and the secondary multi-row winding 7, wound with a PEV wire with multilayer paper-film insulation 9. The value of the resistance of the additional winding is from 25 to 30 kOhm, that is, approximately two times greater than the resistance of the neutron tube at the time the source is triggered. The beginning of H2 of the secondary multi-row winding 7, the beginning of Nnagr. additional 8 and the beginning of the HI primary 6 windings are connected to the metal housing 1 of the generator and the cathode K of the neutron tube 2. The end K2 of the secondary multi-row winding 7 and the end Knagr. additional winding 8 is connected to a bowl-shaped metal screen 13 and the target M of the neutron tube 2.

The windings 6, 7, 8 are wound in one technological process with a PEV and PEV HX wire together with paper-film insulation 9.

The longitudinal axis of the windings of the high-voltage transformer is perpendicular to the axis of the neutron tube 2 and the axis of the case of the neutron generator 1. Due to this arrangement of the windings of the high-voltage transformer with respect to the case, there is no "short-circuit" effect due to the proximity of the case.

Inside the housing 1, a power capacitor of the ion source of the neutron tube 10, a dividing throttle 11, a storage capacitor 12 are placed.

To ensure electrical strength, the generator is filled with a liquid dielectric. A temperature compensator 15 and a high-voltage sealed bushing 16 are installed on the cover of the generator 14.

TKP transformer oil is used as a liquid dielectric in the generator.

The generator operates as follows.

When a start pulse is applied to the control electrode of the switch (not shown in the drawing), the discharge capacitor 12 is discharged to the primary winding 6 of the pulse high-voltage transformer 3.

A voltage pulse of positive polarity with an amplitude of 100 to 120 kV is formed on the secondary winding 7 of the transformer and is transmitted through a bowl-shaped metal screen 13 to the target electrode M of neutron tube 2. At the same time, the ion source of neutron tube 2 produces deuterium ions that are accelerated in the direction of the target. When a neutron tube is bombarded with 2 deuterium ions, neutrons are formed as a result of the nuclear reaction T (d, n) He4.

When the generator is in normal operation, the additional winding 8 does not affect the formation of the accelerating voltage, since the main winding has an order of magnitude lower resistance. When the generator is operating at a time when the source of the neutron tube’s ions does not work, there is no “idle” mode of the high-voltage transformer, since the secondary winding is connected to a parallel additional winding with high resistance, i.e. to a load of 25 to 30 kΩ, which leads to voltage stabilization on the secondary winding of the high-voltage transformer, stabilization of the neutron output and increase the life of the generator.

Due to this technical solution for the location of the transformer windings 3 on the cores 5 of the closed magnetic circuit, the high-voltage winding 7 generates an accelerating voltage pulse, the additional winding 8 performs the function of the load when the ion source of the neutron tube fails.

Thus, the voltage on the secondary winding of the high-voltage transformer 3 is stabilized, which leads to stabilization of the neutron output and an increase in the service life of the generator with minimum dimensions.

Claims (1)

A pulsed neutron generator comprising a neutron tube, a storage capacitor, an inductor and a high-voltage transformer with a multi-row secondary winding with multilayer paper-film insulation, made in a closed magnetic circuit having two cores and two yokes of electrical steel, placed in a sealed enclosure filled with liquid dielectric, the output of the secondary winding is connected to a bowl-shaped screen and a vacuum neutron tube located in it, the longitudinal axes of the transformer windings are located perpendicular to the longitudinal axes of the neutron tube and the casing, characterized in that the primary and secondary windings of the high voltage transformer are made on one core of a closed magnetic circuit, and on the second core there is another high voltage winding wound with a wire with high resistivity, connected to a bowl-shaped screen and the beginning of the secondary winding and body.

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